Screwdriver



D. E. ANDERSON.

SCREWDRIVER. APPucmun rufo wu 2l, |919.

Patented Jan. 25, 1921.v

PATENT oFFlcEf DAVID E. ANDERSON, or sPoKANE, WASHINGTON.

SCREWDRIVER.

Application .filed July 21 ToV aZZ w/Lom t mm/ concern Bc 1t known that I, DAVID E ANDERSON,

Y Va citizen of theUnited `States,residing at Spokane, in the county of Spokane and State of lVashington, haveV invented certain new and useful improvementsY in Screwdrivers, of vwhich the following is a specification. .p

This invention relates to wood working proved means for holdingthe shank of the Y screwdriver detachably in the handle.

The screw-holdingmeans consists speciflcally in a peculiar dove-tailed formation at the tip of the bit coacting with va dovetailed groove or nick in the head of the screw, in conjunction with which a shell is operated longitudinally upon the bit as will be explained below. Y

The handle attaching means'consists preferably in the structure hereinafter more specifically set forth and claimed. Referring to the drawings Figure 1 is a side elevation of this tool complete. y

Fig. 2 is a longitudinal section thereof.

Fig. 3 is a perspective view of the ferrule and stem.

Fig. 4 is a cross section through the bit and shell on the line 4-4 of Fig. 1.

Fig. 5 is an enlarged perspective view of the screw showing the nick in its head. Y

The handle l whichk is preferably of wood has grooves 2 in its body, a reduced waist,- beyond the same a second set of grooves 3, and is then tapered as. at 4 toward its inner end, being provided with an axial bore leading from said inner end inward to receive the stem described below. The outer end or butt of the handle is preferably enlarged and rounded as shown at 5 so as to comfortably rest within the palm of thehand, and the two sets of grooves afford a lirm grasp. Over the tapered inner end 4 slips the ferrule 6 which is preferably retained in place by lingers 7 having inturned pointed tipsB as shown, and the ferrule by preference carries an integral stem 9 from which are struck prongs 10 inclining in the direction seen in Fig. 2 so that the stem may be driven into the bore of the handle when the prongs will engage with the walls of said bore While the Specification of Letters Patent. y Patented Jan. 25, 1921.

1919. Serial No'. 312,293.

lingers will pass through certain 'of the" grooves 3. The tips ofthe lingers may then bebent over and embedded in the waist. The inner end of the ferrule beyond the stem is thickened as s e'en in Fig. 2 to form a head and said head is externally hexagonal as at 11 foi` the application of a wrench when great force is required in turning the screw driver. Formed in the head is a squared lsocket 12 and projecting from said head is a tubular nipple 13 here shown as externally threaded in one direction. A coupling in the shape of a nut 14 has its upper end internally' threadedY to engage the threads on the nipple,'and its lower end reduced and threaded in the opposite direction.

The shank 15 of the screw driver is threaded near its upper end as at 16 to correspond with the threads in the reduced end of the coupling nut 14,l and its extreme upper end isvsquared as at 17 to 'engage the squared socket 12.v Therefore, when the shank is inserted and the coupling turned, it acts as a turn buckle to force the shank through the nipple and into the socket. However1 other means might be employed for detachably connecting the tool shank with the handle. At its lower or working end this shank has a screw driver bit 18 which is flattened as seen in Fig. 4 and tapered as seen in Fig. 2, and its tip is made dove-tailed by being flared as at 19, although it is necessary to have its dove-tail or flared portion on only one side. Uniting the bit and the shank is an integral enlargement 20, externally threaded. Slidable longitudinally on the bit is a shell 21 which at its upper end portion is externally threaded in a direction opposite to the thread of the enlargement. The Shell is flattened toward its lower end portion to slidably coact with the bit and at its lower end is ofl'set at one side into a lip 22. A. coupling in the form of a sleeve 24 is, at its upper end portion, inter- Vnally threaded in one direction to engage the threaded enlargement 20 While at its lower end portion the sleeve is internally threaded in the opposite direction to engage the threaded upper end portion of the shell so that rotation of the sleeve in one direction advances the shell and in the other direction retracts it.

The screw shown in Fig. 5 has its shank S threaded almost or quite up to its head H, and across the top or the face of the head is cut a slot or nick N which is herein shown as lhaving oneiat or upright wall F and the otherwall undercut a little as'shown at U, thereby producing a dove-tailed e'ect,

although the dovetail is only at one side.

Of course, the dove-tail might be Vat both Ysides, and thetip 19 might be shaped to corf i respond.

one end to the other,but these details may I be left to the manufacturer.

Y the nick if the latter tapers vas suggested,

V.and then the shell 21 is run down by turning the coupling nut 24 in the proper direction. This causes thelip 22 to bear on the headof the screw and strain the samal understood as'reserving the widest latitude l v rbit andhaving a lateral lipat its lower end,

downward on the dove-tailed tip, with they effect of locking the screw to the tool so that Y itv may be driven with ease or so that it might be removed in case it had already been driven. Y To disconnect, it is only necessary'- to retract the shell to about the point shown in, Fig. 2, and then-move the tip outof the nick N inv the screw. head. I `desire to be as to changes in details, so long asthey fall within the `spirit ofthe Subjoined claims,

y and especially isv this applicablel with respect to the exact shape of the tip 19 herein 1 calledjdovetailed and the' nick` in the The nick mightialso' taper from" Screw which it fits, as vwell as the means for Y 1. In a screw driver for use with a screw A having adove-tailed nick, thelcombination with abit dove-tailed at its tip toV fit said nick, of a-,shell non-rotatable upon the bit and having a screw engaging lip at its lower end, and means for advanclng-orretractlng Vthe shell at will. f

. 2. In a screw driver for use with a screw having a dove-tailed nick, the`comb1nat1on with a bit dovetailed at yits tip Yto lit said nick and having a flattened body, of a shell flattened-to slidably inclosethe body of the bit but incapable of rotation thereon, ahead on said shell, and a. reversely Vthreaded coupling sleeve engaging theshank ofthe screw driver and saidv head. 1

*i 3. -In a screwdriver, the combination with a shank havinga handle at one end,a fiattenedf bit atthe otherend, and an externally kthreaded enlargement between thel shank and bit, thetipof the latter being dove-tailed,

oia shellv slidable but non-rotatable on said and a'reversely threaded coupling sleeve connectingthe shell lwith said enlargement.

In testimony whereof I aliix my signature. DAVID E. ANDERSON; [L. s.] 

